PURPOSE: To eliminate obstruction from other objects by dividing a binary image in terms of connected areas to select the connected area where the target should occupy as target extraction area.

CONSTITUTION: An image signal taken with a sensor 1 is inputted into an area division circuit 13 passing through a binary coding circuit 2. The area division circuit 13 cleasifies pixels showning a high brightness in terms of pixels connected to each other and outputs data for specifying groups to which pixels all existing should belong to a central value measuring circuit 14. The central value measuring circuit 14 meaures the gravity center, average brightness and area for each group and outputs results to an identrification circuit 16. The identrification circuit 16 identifies the central vaues of the target to be tracked memorized in a memory 15 with those for respective areas to determine area to be tracked within the screen. An extrapolation circuit 17 extrapolates central values of the target using the previous values and new values to memorize the results into the memory 15 as central values for the subsequent target to be tracted while the position of the gravity center is outputted to a driving circuit 5.